Many presently-available marine lifts utilize large and complex lift mechanisms. The size and complexity of many marine lifts limits their use to larger watercraft because smaller vessels cannot support the weight of the lift mechanism. Lifts have been mounted on large luxury watercraft where the lift is configured to raise and lower smaller boats, dinghies, or personal watercraft. Marine lifts may also be mounted to a permanent or semi-permanent marine structure such as a dock, a floating platform, a semi-submersible platform, or a fixed platform. Marine lifts may be used to raise, lower, and transport marine vessels, cargo, and people.
In the case of vessel-mounted marine lifts, lift mechanisms are often mounted on the transom of mono-hulled vessels. This mounting location exposes the lift mechanism to the surrounding environment where waves, water, harsh sunlight, and artificial conditions such as floating debris or a collision may damage the lift mechanism. Outboard mounting of the lift mechanism also hinders diagnostic and repair efforts when a vessel is underway. In order to protect the lift mechanism from the surrounding environment, a cover or other shielding element must be installed which adds additional weight to the marine lift.
Transom-mounted lift mechanisms configured for mono-hulled vessels are difficult to adapt to multi-hull vessels (e.g., catamarans, trimarans, proas, and the like). Mono-hulled vessels provide a large, near-vertical surface for mounting the lift mechanism. In contrast, the decks which interconnect the hulls of a multi-hull vessel such as a catamaran provide only a narrow, elevated mounting surface for the lift mechanism. Transom-mounted lift mechanisms often cannot be adapted to mount to such a narrow, elevated mounting surface.
The length of the marine vessel being carried by a lift mechanism mounted on a multi-hull vessel is constrained by the dimensions of the multi-hull vessel. For example, where a lift mechanism is mounted between the twin hulls of a catamaran, the lift mechanism cannot raise or lower a dinghy longer than the distance between the hulls of the catamaran.
While many marine lifts are capable of raising and lowering significant loads, these lifts often tilt or flex out of level as the load is lowered or raised. Other marine lifts provide a level surface in only one position, such as the raised position. This tilting makes raising and lowering many loads such as smaller boats, dry cargo, and people an unstable and dangerous undertaking. Loads may slide off the marine lift as it ascends, descends, or is in a deployed position. Lack of a level surface also makes many marine lifts dangerous for a person to stand on. Furthermore, this tipping condition may cause a portion of a marine lift to drag in the water and may require an additional locking mechanism to maintain a marine lift platform's position when not in operation.
Given the foregoing, there is a need for simpler lift apparatus which may be adapted for use on multi-hull vessels, lift apparatus wherein the apparatus is at least partially protected from environmental hazards, lift apparatus capable of carrying larger vessels, and lift apparatus configured to provide a level surface as the lift is operated. Lift apparatus that may be raised and lowered via a force provided by a single device are also desired.